And he questioned whether players who choose not to stand "proudly" should be in the country at all.

"Well, I think that's good," Trump said in an interview with Fox News. "I don't think people should be staying in locker rooms, but still I think it's good. You have to stand, proudly, for the national anthem or you shouldn't be playing, you shouldn't be there, maybe you shouldn't be in the country."

Trump's interview with Fox was taped on the sidelines of a roundtable on the MS-13 gang and immigration, on Long Island, N.Y., on Wednesday, but aired Thursday morning on Fox & Friends.

Trump was asked whether he takes credit for the NFL's decision, which he had just been informed about.

"You have to stand proudly for the national anthem," he said. "And the NFL owners did the right thing, if that's what they've done. I think the people pushed it forward; this was not me. I brought it out. I think the people pushed it forward. This country's very smart. We have very smart people. And, you know, that's something ideally could have been taken care of when it first started, would have been a lot easier. But if they did that, they're doing the right thing."

The NFL decision stemmed from discussions arising over players kneeling — in protest of police brutality and racism — during the playing of the national anthem ahead of football games.

There has been a long history in this country of black athletes and political protest.

Fifty years ago, American Olympic champions were sent home from Mexico City after raising gloved fists during the medal ceremony. And the white Australian medalist, who supported them, was only posthumously honored for standing up for human rights.

The two American runners were pallbearers at his funeral.

Muhammad Ali was banned from boxing for three years because he refused to go to Vietnam, citing religious beliefs. The Supreme Court overturned his conviction four years after the fact.

And there was also Curt Flood, who in 1969 protested Major League Baseball's contractual clause calling players the teams' property. Flood likened that to being a "well-paid slave."

There was tremendous backlash from whites. And facing death threats, he left the country. Flood opened a bar in Spain, but abandoned his children — something that left him with guilt so bad that he was admitted to a psychiatric hospital in Spain for treatment.

His case, though, laid the groundwork for modern-day free agency. He was later re-embraced by his sport, after a quarter century, and given the NAACP Jackie Robinson Sports Award for contributions by black athletes.

"Great service" in firing Comey

Trump was also asked in the Fox interview about MS-13 and immigration — and to respond to former FBI Director James Comey's tweets about him. He called Comey a "rotten apple" and said that in firing Comey, he had "done a great service for this country."

Comey had tweeted Wednesday questioning how Republicans would explain to their grandchildren the "lying" coming from the president about "SPYGATE," whether the FBI planted a spy within the Trump campaign.

"Well, I'd actually say, how is he going to explain to his grandchildren all of the lies, the deceit, all of the problems he's caused for this country?" Trump told Fox. "I think a thing I've done for this country, the firing of James Comey is going to go down as a very good thing. FBI is great. I know so many people in the FBI. The FBI is a fantastic institution, but some of the people at the top were rotten apples. James Comey was one of them. I've done a great service for this country by getting rid of him, by firing him."

Trump also showed no signs of compromising his position on immigration. He indicated he would not accept a deal that was short of the pillars he has noted publicly, not just border-wall funding but also an end to the visa lottery program and rules allowing people who gain citizenship to legally bring in family members.Trump indicated he would veto any moderate proposal making its way through the House currently.